docstr: Add 'tag' to the list of langauge tags if not already there.
  
  Returns the integer index of 'tag' in the list of all tags.
docstr_tok: ["Add","'tag","'","to","the","list","of","langauge","tags","if","not","already","there",".","Returns","the","integer","index","of","'tag","'","in","the","list","of","all","tags","."]
code: def addTag(self, tag):
      """Add 'tag' to the list of langauge tags if not already there.
  
      Returns the integer index of 'tag' in the list of all tags.
      """
      try:
          return self.tags.index(tag)
      except ValueError:
          self.tags.append(tag)
          return len(self.tags) - 1
  
file_path: catboost/contrib/python/fonttools/fontTools/ttLib/tables/_l_t_a_g.py
imports: from fontTools.misc.textTools import bytesjoin, tobytes, safeEval
  from .None import DefaultTable
  import struct
label_desc: Use image node_id 2 for calling the table__l_t_a_g obj's underlying member method code with example usage: obj.addTag(tag) and returns: self, unknown